Curve-drawing instrument.



L. T. ROBINSON. CURVE DRAWING INSTRUMENT.

APPLIOATION FILED MAR.80,1903.

Patented NOV. 1, 1910.

Lew/is T. Robinson.

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L. Tn ROBINSUN.

CURVE DRAWING INSTRUMENT.

AIPLIOATION FILED MAILSO, 190s Patented Nov. 1,1910.

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- \A/JTNESSES INVEHTOFQ LeWisTRobinSDn q flttq.

UNITED STATES PATENT OFFICE.

LEWIS T. ROBINSON, OF SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL ELECTRI COMPANY, .A CORPORATION OF NEW YORK.

CURVE-DRAWING INSTRUMENT.

' Specification of Letters Patent.

Patented Nov. 1, 1910.

Application filed March so, 1903. Serial No. 150,099.

To all whom it may concern:

Be it known that I, LEWIS T. ROBINSON, a citizen of the United States, residing at Schenectady, c'ounty of Schenectady, State of New York, have invented certain new and useful Improvements in Curve-Drawing Instruments, of which the following is a specification.

My invention relates to an improved construction of instruments of that character in which a record is made showing different values of a variable quantity.

More particularly my invention relates to an instrument with which a record is made upon a record surface having a'progressive movement, the speed of themovement being usually some function of the time. Instruments of this character have been constructed in which a pencil, pen or other marking instrument carried by a member moving to different positions upon changes in the .value of the variable quantity has been constantly in contact with the movable record surface. This construction is not desirable in those cases where the force producing the movement of the marking element is very slight owing to the considerable friction necessarily existing between the'n'iarking element and the record surface. In another type of recording instrument, the marking element moves normally out of engagementwith the record surface and engages the record surface only The intervals engagemei'its of this type of instrument has heretofore been controlled by time mechanism such as a spring motor. The record obtained by this instrument owing to the lack of continuity is not as satisfactory for all purposes as those obtained by the first The last dementioned type of instrument. scribed instrument however is free from the continuous frictional engagement between the marking element and the record surface which exists in the first mentioned instrument and which as I have before said may be detrimental undercertain circumstances.

The object of my present invention is the construction of an instrument possessing the advantageous features of both types of the instruments described above without-the disadvantages mentioned. I obtain'this result by the employment ofa marking element moving normally out of contact with the hetic means for forcing the marking element into contact with the record surface and an electromagnet circuit-making and breaking device or buzzer for causing an intermittent energization of the electromagnetic means which causes the engagement between the marking element and the record surface.

For a better understanding of my inven tion reference may be had to the drawings in which I have illustrated several embodiments of my invention.

Of thedrawings Figure 1 is a side elevation, Fig. 2 a plan view, and Fig. 3 an end elevation showing a portion of the construction in Fig. 1 viewed in the direction of the arrow on Fig. 1, all illustrating one form of my invention; Fig. 4 is a view taken similarly to Fig. 1, amlFig. 5 a view taken similarly to Fig. 3 showing a modified form of the invention; Fig. (3 is a sectional end elevation, and Fig. 7 is a plan view illustrating details of another modified form of my invention; and Fig. 8 is a partial sectional elevation illustrating details of the construc tion illustrated in Figs. 1, 2 and 3.

In all of the forms of my invention, the mechanism is supported ,upon a base -1. The member moving in response to changes in the value of a variable quantity is an arm 2 which is shown as carried by the oscillating vertical shaft 8 upon which is mounted the movable coil 4: of a low torque voltmeter 5 which is suitably supported from a basal.

In the construction illustrated in Figs. 1, 2, 3, and 8 the arm'2 carries at its outer end a marking element 6 having conical ends which extend at right angles to the plane of movement of the arm 2 as shown. This arm, sweeps over the top of a bar or platform 7 parallel to the chord of the arc traversed by the marking element 6. The bar 7 is supported at the top of a pair of vertical posts 8 8 extending upward from the base 1. A record surface 9 is fed from a supply roll 10 across the platform 7 by any suitable mechanism as for instance a sprin motor conventionally indicated at 11 suitabletransspectively.

Guides 14:" extend from the post 8 and in these guides a bar 15 is slidingly mounted The bar 15 carries at its upper end a crossbar 16 from which'extend a 'pair of vertical posts 17 which in turn carry another crossbar 18 parallel to the bar 16. The bars 16 and 18, and the posts 17 form a yoke which embraces the bar pr platform 7. A post 19 extends upward from the top bar 18 in alinement with the post 15. A long arm 20 adjust-ably mounted upon the post 19 extends parallel to the bar 7. The arm 20 has a wide bearing surface 21 at its bottom which overhangs the marking element 6 in all 0 its positions.

An electromagnet 22' having vertical cores is-carried by the support 1 between the posts 8 and 8. i The armature 23 for this electromagnet is carried by a substantially horizontal bar 22 pirotally connected at one end to the post 8 and at the other end to the bar 15. A spring 21 connected at one end to the upper side of a bar 22 and at the other end to the lower side'of the platform 7 tends to hold the bar 22 in the position shown in Fig. 3. In this position the bar 15 is so held that the hammer arm 20 is out of contact with the marking element carried at the end of the arm 2. A bracket 25 carried by the post'8 'has extending from its lower side a brush or flexible, contact' member 26 which engages with a contact device 27 mounted pon the upper side of the bar 22 when tbe bar 22 is in the position shown in Fig. 3. The contact 27 is in circuit with the windings of the coil 22. The binding post 28 carried by the bracket 25 is in electrical contact with the contact member 26 and forms one terminal of the electromagnet. The other'terminal has not been illustrated in the drawings.

It will readily be understood that the passage of current through the windings of the electromagnet 22 will cause the armature 23 to be attracted. This will reciprocate the bar 15 and the hammer 20, causing the marking element to be forced against the record ribbon to make a record upon the record strip. \Vhen the windings of the electromagnet 22 are energized and the armature 23 moves downward, the circuitthrough the windings of the electromagnet is broken by the separation of the contacts 26 and 27 which then takes place. This causes the electromagnet to be deenergizcd, whereupon the spring 2-lmoves the mechanism back into the position shown in Fig 3. spring 29 surrounding the bar 15 and extending between the lower guide 14 and a collar 30 adjustably secured on the bar 1 forms a means for regulating the upward 'movement of the bar 22 under the action of the spring 24-. When the arm 20 is moved into the )osition shown in F 3, due to the action 0 the spring 21, the arm 2 is free to oscillate in accordance with the changes in the torque tending to more the coil 1. As soon as the contacts 28 and 27 engage again. the circuit through the winding of the electromagnet 22 is again closed and the armature and the mechanism connected to it again drawn downwardf The rapidity with which the reciprocationof ,thc armature 23 and the hannner '10 takes place depends upon the proportioning of the rarious parts of the make aml break (lCYHQ. but in any case is very rapid. The result of this rapid succession of engagements be tween the marking element and the record surface is a record which is practically continuous.

In the construction shown in Figs. l and 5, the platform 7 corresponding to the platform 7 heretofore mentioned is formed by the end of the core of an elcctronmgnet 31 which is supported on a post 32 rising from the base 1. The post 32 also carries an clcctromagnet. :22" similar in function to the elcctromagnct- 22. The countcrlmlanced armature 33 for the electromagnet 22" is pivoted to the post 32 and is adapted to engage and disengage a contact 31 -arried by the post 32 under the alternate action of the spring 35 and the elcctrmnagnct 22". Preferably the clrctroinaguels 2ll.and 22" are in circuit. with one another and hence are both energized and decnergized simultaneously. When the elcctromagnet 31 is energized the marking element (5 whi h is formed of magnetic material such a: soft iron is attracted. This causes the pointed end of the marking element to press against the ribbon 12 and make a. record on the record strip 9. \Vhilc l have described the magnets 22" and 31 as being in the same circuit, it will be readily understood that they might be in dill'erent circuits and that the armature 33 could open and close both 1 of these circuits. By making the core .of

the elcctromagnet 2&1, substantially rectangular in crosssectimraml with its width equal to the. width of the record strip the marking element 6' will be pulled directly down regardless of the positioinof its path in which it may happen \to be located whenever the clcctromagnet 31 is energized.

The construction illustrated in Figs. 0 and 7 differs from the construction shown in Figs. 1. 2 and 3 in that the marking element (3 does not impinge directly against the record ribbon but againstonc of a series of plungcrs 3(3. The plungcrs so are mount ed to reciprocate vertically in guidcways 3T plungers and bear against the under side of the collar 39 in such manner as to hold the plunger-s 36 out of contact with the record sheet as shown in Fig. ti. lleads it are formed at the upper end of the plungrera against which the marking element .(3 iinpinges when the hammer 2O rcciprocated.

The marking ends of the plungers are spaced equally along" the width of the record sheet. ,In case the inatrument is of uch a character that proportional changes of volt'age do not n'odnce eta-responding angular IHOVOHHI'ltS of the arm 2, the heads ll may -be displaced as shown in Fig. 7 so as to correct for the irregular arc movement oi the arm 3. It will readily be understood that the plungcra nay be arranged in a straight line at right angles to the direction oi. move ment ot the record surface in which case the headacould be displaced in lines parallel. to the directioi'i of movement of the record SltYftlCO or the marking element t' might have an elongated bearing edge so that an engagementbctwceu the marking element and the heads of the plunger-a would always be made when the hammer 20 was ret-iprocated.

It will of murec be understood that my invention can be employed in connection with other measuring instruments than volt: meters and that many modifications in the construction shown may he made without mark it departing from the spirit of my invention for instance instead of employing a record ribbon such as I have described, I might dispense with it. and cause the marking ele-' ment to impinge directly upon the paperto impact.

\Vhat: I claim as new, and desire to secure by Letters Patent of the United States is-- 1.. in ctnnbiruititm, means for supporting a record surface, a movable meter element a series of marking devices'ar ringed between the i'noving element and the record surface, and electromagnetic means for causing the movingelement to engage with the particular marking device between it; and the record surface to cause said marking device to make a record upon the record surface.

2. in combination an element moving in a path, a series; oi marking devices arranged in proximity to said path, each of said de- Vices being provided with a stylus and. an engaging portiom the engaging portions of Some of the marking devices being displaced with reference to the corresponding Styluses. and means for causingthe moving element to engage with the engaging portion of the marking devices in proximity to the point in the path at which the luovingelcinent may happen to be.

in witness whereot l have hereunto vact any band this 26th day of lylarch, i903.

LEWIS it. ROBl NSON.

Witnesses Ben J AMIN B. HULL, HELEN ORFORD.

by puncturingitor merely by 

